Revoking Leukemia's License to Kill

Fighting leukemia may soon become as easy as getting a shot. Cancer researchers at the University of Texas are testing a vaccine that can put one form of the disease into remission.

The vaccine fights myelogenous leukemia, which strikes 16,000 people a year, many of them senior citizens. So far tests have been promising. The vaccine slowed the cancer to a crawl in 20 of 33 cases—with few side effects. “We treated people who wouldn’t be expected to live three months,” says Jeffrey Molldrem, an immunologist with the university’s M. D. Anderson Cancer Center in Houston. “So the fact that some lived four years is quite surprising. That some actually went into remission is equally astounding.”

In both acute and chronic myelogenous leukemia, immature white blood cells in the bone marrow multiply out of control. They fail to fight off infections as they are meant to and collect dangerously in organs, blocking their functions. The vaccine sets off an immune response using a piece of a protein, called PR1 peptide, found on the surface of leukemia cells. The body recognizes the peptides as foreign invaders and, as a result, attacks the leukemia cells. Other cancer vaccines have been created, Molldrem says, but this is the first one for leukemia that seems to work.

The drug must now go through another round of clinical trials. If they are all successful, it would be three to four years before the vaccine is available.